Rapid photographic processing solutions and method

ABSTRACT

Rapid processing of exposed photosensitive materials is achieved by the use of alkaline hydroquinone developers at an elevated temperature of from 75* to 125* F.

States Patent Apr. 4, 1972 [54] RAPID PHOTOGRAPHIC PROCESSING SOLUTIONS AND METHOD [72] Inventor: Murray Friedel, North Miami Beach, Flat.

[73] Assignee: Visual Graphics Corporation, New York,

[22] Filed: Feb. 13, 1970 [21] Appl. No.: 11,312

[52] US. Cl ..96/50, 96/63, 96/61, 96/66 [51] Int. Cl ..G03c 5/26, G03c 5/24, G03c 5/30 [58] Field of Search ..96/48 QP, 66, 66.1, 61,50, 96/63 [56] References Cited UNlTED STATES PATENTS 3,345,174 10/1967 Dotson ..96/61 OTHER PUBLICATIONS Primary Examiner-Norman G. Torchin. Assistant ExaminerM. F. Kelley Att0rneyAlbert F. Kronman [57] ABSTRACT Rapid processing of exposed photosensitive materials is achieved by the use of alkaline hydroquinone developers at an elevated temperature of from 75 to 125 F.

3 Claims, No Drawings BACKGROUND OF THE INVENTION Various types of materials and compositions have been produced in the photographic art in an effort to shorten the time required for photographic processing. However, prior art materials and compositions have achieved greater speed at the expense of quality, stability and economy of the final product. Accordingly, it is an object of the present invention to provide for the rapid processing of exposed photosensitive materials in less than one-half a minute. Another object of the present invention is to process exposed photographic materials at high speeds without sacrificing quality, stability and at no great increase in cost. Processing according to the present invention employs conventional inexpensive photosensitive materials and achieves the excellent results associated with such materials.

SUMMARY OF THE INVENTION Conventional, exposed photosensitive materials are passed through a four bath processor in which the solutions are maintained at a temperature of from 75 to 125 F. The first two baths, comprising the development section, contain hydroquinone in the first bath and an alkaline in the second bath. Fixing and wash are carried out in the last two baths.

A fifth bath incorporating glycerine for prevention of emulsion cracking may be used to increase the life and permanence of the finished product.

DESCRIPTION OF THE PREFERRED EMBODIMENT In carrying out the processing of exposed photosensitive materials according to the present invention, the said materials are rapidly passed through a series of four baths. The solutions in the baths are maintained at an elevated temperature of from 75 to 125 F. by thermostatically controlled means well known in the art. The elevated temperatures accelerate the developing and fixing reactions. It has been found possible, by employing the compositions of the present invention, to have the photosensitive material traverse all of the four baths in less than one-halfminute.

In addition, the speed of a high-alkaline hydroquinone development is achieved, while greatly extending the activity and useful life of the solution. These advantages are secured by separating the components of the developing solutions into two stable baths. The first bath serves to impregnate the photosensitive material with developing agents at a pH which will ensure long solution life and stability. The pH necessary for rapid development is provided by the second bath. The hydroquinone is thus not subject to in situ oxidation and only the small quantity of hydroquinone carried over into the alkaline second bath is subject to chemical reaction.

A preferred first bath solution according to the present invention consists of the following:

Parts by Weight Water 86.73 Sodium bisulfite 0.70 Benzotriazole 0.02 Hydroquinone 4.7l Ethylene glycol 7.73

Sodium sulfite 0.11

The ethylene glycol increases the solubility of the hydroquinone in the solution thereby increasing the amount of hydroquinone which will be absorbed into the photosensitive material.

A preferred second bath solution according to the present invention consists of the following:

Parts by Weight Water 8809 Potassium bromide 0.65 Sodium sulfite 5.87 Trisodium phosphate L47 Sodium hydroxide 3.92

As the photosensitive material emerges from the second bath solution it is fully developed. The developing time is of the order of 14 seconds due to the combination of the high concentration of the first solution, the high pH of the second solution and the elevated temperatures (75 to F.) of both solutions.

The developed photosensitive material is next fixed in the third bath which produces rapid fixing. A preferred fixing solution according to the present invention consists of the following:

Parts by Weight Ammonium thiosulphate (50%) 35.72

Ammonium thiocyanate (50%) I186 Water 46.42

Another fixing solution according to the present invention consists of the following:

Parts by Weight Water 54.75

Monosodium phosphate 2.78

Sodium sulfite l.2l

Ammonium thiocyanate (5071) 12.12

Ammonium thiosulfate (50%) 29.14

As the photosensitive material emerges from the third or fixing bath, through which it passes in about seven seconds, it is washed in the fourth bath for approximately the same length of time. A preferred fourth bath consists of:

Parts by Weight Ammonium thiosulfate (5071) 10.71

Water 89.29

The use of thiosulfate in the final bath in dilute quantity provides sufficient complexing to tie up free silver ionsand still wash the reaction by-products in sufficient quantity to provide good short-term fixing.

In the event that permanent, fully fixed photographic products are desired a fifth bath may be employed.

A satisfactory fifth bath to give the photographic materials archival quality, according to thepresent invention comprises the following:

Parts by Weight Water 94.75 Sodium benzoate 0.2 8 Isopropyl alcohol L42 Acetic acid (50%) L42 Glycerine I .42 Ethylene glycol 0.7l

The developed photographic materials should remain in this last bath for approximately 7 seconds. i

From the foregoing it will'be seen that there has been pro vided a series of solutions which when employed at the specified temperatures will produce high quality fully processed photographic materials in a very short space of time using well known inexpensive and available photosensitive papers, films and the like.

Having thus fully described the invention, what is claimed as new and desired to be secured by Letters Patents of the United States, is:

1. A method for increasing the speed for developing exposed photosensitive materials comprising, in combination, developing said materials in two different baths, the first bath containing 86.73 percent by weight of water, 0.70 percent by weight sodium bisulfite, 0.02 percent by weight of benxotriazole, at least 4.71 percent by weight of hydroquinone, 7.73 percent by weight of ethylene glycol, 0.11 percent by weight of sodium sulfite; the second bath containing 88.09 percent by weight of water, 0.65 percent by weight of potassium bromide, 5.87 percent by weight of sodium sulfite, 1.47 percent by weight of trisodium phosphate, and 3.92 percent by weight of sodium hydroxide; then fixing said material by passing them through a third bath containing some 29.14 to 35.72 percent by weight of ammonium thiosulphate (50 percent), 12.2 to 17.86 percent by weight of ammonium thiocyanate (50 percent), 46.42 to 54.75 percent by weight of water; and washing said materials by passing them through a fourth bath containing 10.71 percent by weight of ammonium thiosulfate (50 percent), 89.29 percent by weight of water; said first, second, third and fourth baths being employed at a temperature of from 75 to 125 F.; the total passage of time of said materials through said first and second baths being of the order of 14 seconds and the passage of time in said third and fourth baths being about 7 seconds.

2. The method of claim 1, wherein said third bath contains also from 0 to 2.78 percent by weight of monosodium phosphate and 0 to 1.21 percent by weight of sodium sulfite.

3. The method of claim 1, wherein the washed materials are fully fixed by passing them for about 7 seconds at about 75 and F. through a fifth bath containing 94.75 percent by weight of water, 0.28 percent by weight of sodium benzoate, 1.42 percent by weight of isopropyl alcohol, 1.42 percent by weight of acetic acid, 1.42 percent by weight of glycerine, and 0.71 percent by weight of ethylene glycol. 

2. The method of claim 1, wherein said third bath contains also from 0 to 2.78 percent by weight of monosodium phosphate and 0 to 1.21 percent by weight of sodium sulfite.
 3. The method of claim 1, wherein the washed materials are fully fixed by passing them for about 7 seconds at about 75* and 120* F. through a fifth bath containing 94.75 percent by weight of water, 0.28 percent by weight of sodium benzoate, 1.42 percent by weight of isopropyl alcohol, 1.42 percent by weight of acetic acid, 1.42 percent by weight of glycerine, and 0.71 percent by weight of ethylene glycol. 